Poster A79, Saturday, March 24, 1:30–3:30 pm, Exhibit Hall C
EEG-Based Source Imaging Revealed Lower Beta-Band Top-Down Modulation of Early Visual Areas
Hua Zhong1, Guang Ouyang1, Yunqing Hua1, Akaysha Tang1; 1The Laboratory of Neuroscience for Education, Faculty of Education, The University of Hong Kong
Top-down neural feedback from motor system to early visual areas is known to influence perceptual processing. These top-down feedbacks have been extensively studied under various task conditions using different brain imaging methods. Here, building upon the study by Ouyang et al (submitted to CNS 2018, poster ID 713), we applied a blind source separation algorithm (second-order blind identification, SOBI) to high-density EEG (128 channels) data collected from a color visual oddball task and examined how neural activities in early visual areas in the human brain are modulated by top-down input associated with the action of a button press response. We found that the button press response consistently evoked an oscillatory response in the early visual areas (BA17, 18, 19) across all 9 participants observed. We applied Morlet wavelet transformation to the time series of single trial neural source activities within a time window surrounding the time of button press response. The wavelet analysis revealed a clear motor response-elicited enhanced oscillatory activity pattern in the frequency band centred at 13 Hz, covering a width of 4 Hz, with peak power latency of 582+/-35 ms. These results demonstrate that (1) SOBI-aided source analysis allows the measurement of top-down signals fed back into specific early visual areas; (2) these top-down feedback signals are in the lower beta band, consistent with findings from non-human primate studies.
Topic Area: METHODS: Neuroimaging